Carriers, such as carriers in the form of tapes, are often used for storing packaged semiconductor devices. FIG. 1 is an isometric view of a conventional offloading apparatus 10 comprising a guiding track 16 for guiding a carrier tape 12 for storing electronic devices. The guiding track 16 guides the carrier tape 12 lengthwise and there is a recess 14 along the guiding track 16 where the carrier tape 12 is exposed for receiving electronic devices. A pick head 18 picks up electronic devices and places them onto the carrier tape 12 through the recess. Typically, the carrier tapes 12 used are made from plastic.
FIG. 2 is a cross-sectional view of a conventional plastic carrier tape 12 comprising vacuum holes 24 for securing electronic devices on the plastic carrier tape 12 using vacuum suction. The plastic carrier tape 12 has a plurality of pockets 22, each for storing a single electronic device 20. The pockets 22 have pre-formed vacuum holes 24 at their base portions underneath where the electronic devices 20 are placed so that the devices can be held against the base portions by vacuum suction force. A vacuum port 26 is located below the vacuum holes 24 to provide such vacuum suction force to hold the electronic devices 20.
Thus, the guiding track 16 indexes the plastic carrier tape 12 to present an empty pocket 22 to the pick head 18. The pick head 18 picks up an electronic device 20 and places the electronic device 20 into an empty pocket 24 through the recess 14. While in the pocket 22, the electronic device 20 is held by vacuum suction generated by the vacuum port 26 to secure the electronic device 20 so that it does not jump out of the pocket 22 due to turbulence during conveyance along the guiding track 16.
Whilst this approach is sufficient for conventional electronic devices, for electronic devices 20 that are relatively smaller in size, it is not feasible to form vacuum holes 24 at the base portions of these plastic carrier tapes 12. Without an adequate holding force to secure the electronic devices 20 in the pockets 22, the smaller electronic devices 20 will face a significant risk of jumping out of the plastic carrier tape 12 or flipping during their transportation due to turbulence. This will result in unnecessary yield loss.
It would be beneficial to develop another way of securing the small electronic devices 20 in the pockets 22 during their transportation that is capable of exerting a retention force to retain the small electronic devices more securely to reduce unnecessary yield loss.